1. Field of the Invention
This invention relates generally to coating application devices. More particularly, the invention pertains to a floor coating application device for applying protective, functional or decorative coatings to planar surfaces, such as hardwood floors, concrete floors, and the like.
2. State of the Art
Various materials are used as protective, functional or decorative coatings for planar surfaces. Many coating materials are applied to surfaces in a liquid state, later drying to form the desired coating. It is not uncommon to apply more than one layer of a coating to a particular surface in order to increase the thickness of the overall coating and thereby improve the resiliency, durability, and longevity of the surface. The coating material is typically applied to the surface and then uniformly distributed over the surface and smoothed by an application device.
The thickness of each layer of coating material distributed over the surface varies with the type of coating material used and the amount of pressure used to apply the coating material. Because of the dependency of the coating thickness on the characteristics of the coating material, the manufactures of coating materials provide guidelines which detail the amount of coating material necessary to cover a given surface area. If the guidelines are followed, a near perfect coating thickness should be achieved. However, there are a few factors that make it difficult to achieve such a perfect coating.
The liquid state of coating materials makes it difficult to evenly spread the coating over a given surface area. The thickness of the wet coating layer often depends upon the amount of force used to spread the coating over a surface. The force originates from the application device which is typically controlled by a human operator. Many of the individuals practicing the art of coating floors have developed the skill required to judge how much force must be applied to an application device to achieve a desired coating thickness. Additionally, the speed at which the coating is spread over the surface by an operator can also make a difference in the coating thickness. Although a person spreading the coating layer may become fairly proficient in laying consistent coatings, those who are inexperienced or who are laying a new type of coating are often unable to maintain the uniformity desired in the coating thickness. Because of these human variables, the wet thickness of the coating will often vary. As the coating then dries, the thickness of the coating layer decreases and all of the imperfections in the wet thickness are magnified.
The ideal finished surface is one having multiple coating layers, dried to a uniform thickness, with as few flaws or irregularities as possible. Just as flaws and irregularities are caused by the inconsistent force and speed used to spread the coating layers, such things as the shedding of particles from the application device onto the coating layer, or particulate matter settling on the coating layers during the drying process or air bubbles forming in the liquid coating, may also cause flaws and imperfections in the coating surface. Because the coating layers are typically thin, such flaws and variances are compounded with each additional layer of coating material. To avoid such problems, application devices have been developed which decrease the amount of imperfections that occur in coating layers and aid in the application of uniform, thin layers of coating material to planar surfaces.
Typically, when an application device is used to apply a coating material to a planar surface a portion of the coating material is first applied to the surface and the application device is used to evenly spread the coating over the surface. This is accomplished by pushing or pulling the application device over the surface area upon which a coating material has been deposited. As the leading edge of the application device contacts the liquid coating material, the coating material is displaced across the edge of the application device. As the application device is pushed or pulled over the surface, a layer of coating material is deposited between the application device and the surface being coated. Occasionally, a mechanical device is used to push or pull the application device over the surface and thereby spread the coating material.
As coating material builds up on the application device the excess coating material is squeezed out of the applicator. This is accomplished by tapping, knocking, slapping, or pressing the application device against a hard surface to force the excess coating out of the applicator material. After the completion of a coating layer the applicator must be cleaned if it is to be used again. The applicator is cleaned by immersing the entire piece of material in a solvent. The applicator may then be reattached to the application device and the process of coating a surface may begin again.
There are a number of different types of floor coating application devices currently being used to apply coatings to planar surfaces such as hardwood and cement floors. One such application device consists of a body piece, an applicator and a handle used to guide the device. The body of the device is essentially a rectangular block made of a rigid material. The body typically has a length of approximately eighteen inches, a width of four to six inches and a thickness sufficient to maintain the rigidity of the body. These dimensions create two opposing sides with large surface areas. The body acts as a rigid support to which an applicator may be fastened. An applicator is a piece of material, such as lamb's wool or synthetic lamb's wool, which wraps around the body in such a manner that one of the two sides of the body is completely covered by the applicator. The edges of the applicator are secured to the second side of the body so that the applicator is fixed on the body and will not move when subjected to external forces. A handle is typically attached to the exposed second side of the body, extending in an upwardly direction.
A second type of application device is similar to the first device in all respects except for the applicator. Instead of having an applicator which is fastened about the body of the application device, the applicator material is directly attached to the body. Typically, the applicator material is a flocking or set of bristles which are glued or permanently attached to the application device.
A third type of application device consists of a tubular body to which an applicator is permanently attached. The applicator is securely fastened around the circumference of the tubular body. The tubular body typically contains a flat plate attached thereto for a detachable handle to be secured. This type of application device provides a smaller contact surface area then the device mentioned above.
Although the application devices currently used to apply coating materials to planar surfaces are sufficient to achieve adequate floor coatings, there are a number of problems associated with their use. One of those problems is wicking. As an application device spreads coating material over a surface, the coating material wicks throughout the applicator, saturating it with the coating material. Coating buildup on the applicator caused by such wicking can result in the uneven distribution of coating material over the surface. Excess coating material drips off of the back or the sides of the application device during normal use or splatters when trying to remove the excess coating from the applicator. The droplets disrupt the uniform nature of the coated surface, decreasing the quality of the finished coating.
Additionally, wicking presents undesired results when attempting to apply coating to a planar surface which contacts a perpendicular surface, such as where a floor and a wall join. Application of the coating material to the entire floor necessitates that the outer edges of the application device contact the wall at some point. If this contact occurs after coating material has wicked through the applicator, the coating is applied to the wall. This is undesirable.
Current solutions to rid the application device of unwanted coating buildup caused by wicking include forcing the excess coating material out of the applicator by squeezing the applicator against a hard surface or replacing the applicator. Often times, the squeezing or slapping of the applicator against a surface to rid the application device of the unwanted coating material results in a spattering of coating droplets which can disrupt a uniform surface which has already been coated. Replacing the applicator is also disadvantageous. Removing the applicator from the current application devices is time consuming and often very messy. The tubular application devices pose significant cleaning problems because the entire tube must be immersed in a solvent. This requires that large cleaning vessels filled with large amounts of solvent are kept on hand to clean the applicators.
Another problem associated with the application of coating materials to planar surfaces is the unevenness of the coating layers. The four to six inch wide application device tends to produce more variance in the thickness of coating layers than application devices with smaller application surface areas. In addition, the larger surface area requires a larger applicator, which provides more wool which can shed off of the applicator and deposit flaws in the coating layers. Likewise, the application device having the permanent applicator material attached thereto has been found to be prone to excess shedding of material into the coating layers. Such shedding creates flaws and imperfections in the coating layers which is undesirable.
The thickness of each coating layer is dependent upon the pressure applied to the application device by the individual spreading the coating. Various coatings have different viscosities, thus the pressure applied by the operator varies the thickness of the coating being applied. Typically, an operator becomes proficient with the various coatings and is able to apply the desired pressure necessary to achieve the desired coating thickness. However, this does not provide a standard, consistent force which produces uniform coating layers because it is very difficult to maintain a constant, and consistent downward force on the application device.